Matthew 18:11 (a) We should note that in this Scripture the word "seek" does not occur. It is speaking of a child that is not saved, but is in sin. He sins because he is born as a sinner, and the word "lost" indicates that he is outside the family of GOD and on the way to a lost eternity.

Luke 19:10 (a) The unsaved person in this verse refers to an adult. That one needs to be sought after as well as needs to be found. He has deliberately gone astray and turned to his own way. GOD seeks him out as a shepherd seeks out the lost sheep, or as Saul sought the lost asses. The lost man is unsaved; he is in his sins; he does not know where he is going; he does not know GOD; he is in the dark. (See Ephesians 2:12).

2 Corinthians 4:3 (a) The word is used in this passage in the same way as in the former passages. We learn here of a different characteristic of the unsaved man, i.e., he does not understand GOD's Word or GOD's Gospel. He can talk intelligently about business or pleasure, science or arts, but has no understanding of GOD's truth, GOD's Gospel, and GOD's Son. For this reason he is said to be lost, he is on his way to hell.

Bibliography Information
Watson, Walter. Entry for 'Lost'. Wilson's Dictoinary of Bible Types. https://www.studylight.org/dictionaries/eng/wdt/l/lost.html. 1957.

Bible Dictionaries Lost

Wilson's Dictionary of Bible Types

Bible Dictionaries
Lost